The AD722 is a low cost RGB to NTSC/PAL Encoder that converts red, green and blue color component signals into their corresponding luminance (baseband amplitude) and chrominance (subcarrier amplitude and phase) signals in accordance with either NTSC or PAL standards. These two outputs are also combined to provide composite video output. All three outputs can simultaneously drive 75 (ohm), reverse-terminated cables. All logical inputs are CMOS compatible. The chip operates from a single +5 V supply. No external delay lines or filters are required. The AD722 may be powered down when not in use.

The AD722 accepts either FSC or 4FSC clock. When a clock is not available, a low cost parallel-resonant crystal (3.58 MHz (NTSC) or 4.43 MHz (PAL)) and the AD722's on-chip oscillator generate the necessary subcarrier clock. The AD722 also accepts the subcarrier clock from an external video source.

The interface to VGA Controllers and MPEG Video Decoders is simple: an on-chip logic "XNOR" accepts the available vertical (VSYNC) and horizontal sync (HSYNC) signals and creates the composite sync (CSYNC) signal on-chip. If available, the AD722 will also accept a standard CSYNC signal by connecting VSYNC to +5 V and applying CSYNC to HSYNC pin. The AD722 contains decoding logic to identify valid HSYNC pulses for correct burst insertion.

Delays in the U and V chroma filters are matched by an on-chip sampled-data delay line in the Y signal path. To prevent aliasing, a prefilter at 5 MHz is included ahead of the delay line and a post-filter at 5 MHz is added after the delay line to suppress harmonics in the output. These low-pass filters are optimized for minimum pulse overshoot. The overall luma delay, relative to chroma, has been designed to be 170 ns, which precompensates for delays in the filters used in the IF section of a television receiver. This precompensation delay is already present in TV broadcasts. The AD722 comes in a space-saving SOIC and is specified for the 0°C to +70°C commercial temperature range.